Machine for perforating high density poly-ethylene film or the like film material

ABSTRACT

A machine for perforating high density polyethylene film comprising a feed roller, cooperating male and female rollers between which the film passes for perforation and a take-up roller for receiving the perforated film material. A plurality of blade members are housed within the male roller and under the influence of adjustable indexing means are adapted for reciprocal motion relative to the surface of the male roller. In the vicinity of the female roller preselected ones of the blade members are caused to project from the surface of the male roller and to enter a complementary recess in the female roller to perforate the film material as it passes between the male and female rollers. The longitudinal distance between the perforations on the film is determined by the selection of blade members caused to project from the male roller during each revolution of the male roller.

This invention relates to a machine for perforating high densitypolyethylene film or the like sheet material.

Known constructions of machines for perforating film material are ingeneral of complex construction and suffer from the disadvantagesinherent with complex machinery namely high maintainance and spare partcosts. Additionally the known machines only operate at relatively lowspeeds and yet do not produce a consistently good quality product. It isan object of the present invention to overcome the stated disadvantagesof the known machines by providing a machine of relatively simpleconstruction which can operate at high speed.

Accordingly the present invention provides a machine for perforatinghigh density polyethylene film or the like film material, comprising afeed roller for supplying film material to be perforated from a rollerthereof, cooperating male and female rollers between which film materialfrom the feed roller passes for perforation and a take up means forreceiving the perforated film material. A plurality of blade members areprovided, each mounted for reciprocal motion relative to the surface ofthe male roller between a first position wherein the blade memberprojects from the surface of the male roller and a second positionwherein the blade member is retracted into the male roller. Anadjustable indexing means is provided which cooperates with the blademembers such that, at least in the vicinity of the female roller,preselected ones of the blade members are caused to project from thesurface of the male roller and the non-selected blade members are causedto be in the retracted positions, whereby in use a preselected blademember projecting from the surface of the male roller enters acomplementary recess in the female roller to perforate film materialpassing between the said male and female rollers.

In an embodiment of the invention it is possible to adjust the spacingof the perforations in the film material. This is achieved by suitablyadjusting the indexing means.

The invention will be understood from the following description of apreferred embodiment thereof given by way of example only with referenceto the accompanying drawings in which:

FIG. 1 is a diagrammatic front view of a first embodiment of a machineaccording to the present invention, the support structure andconventional drive mechanisms being omitted for the sake of clarity;

FIG. 2 is a diagrammatic side view of the machine of FIG. 1;

FIG. 3 is a diagrammatic detail side view of the male roller indexingmechanism;

FIG. 4 is a partial front view of the mating of the male and femalerollers;

FIG. 5 is an enlarged detail of the mating of a blade member on the maleroller with a recess on the female roller;

FIG. 6 is a view of a longitudinal line of perforations as applied bythe machine of FIGS. 1-5 of the accompanying drawings to a sheet of filmor the like sheet material;

FIG. 7 is a diagrammatic view of the indexing mechanism which is housedwithin the hollow drum of the machine illustrated in FIGS. 1-6 of thedrawings;

Referring to the accompanying drawings there is illustrated a machinefor perforating high density polyethylene film. The machine comprises aframe structure 10 having supported thereon and located in an operativeposition thereon a film feed roller 11, for supplying film material tobe perforated from a roll thereof, a film take-up roller 12, andcooperating male and female rollers 13 and 14 respectively. The filmtake-up roller 12 and the male roller 13 are driven rollers and thedrive means is a conventional electric motor (not shown). The feedroller 11 is an idler and the female roller 14 is directly gearedthrough gears 15 and 16 and gears 17 and 18 to the driven male roller13. In use, the film material 21 passes between the male and femalerollers for perforation, as shown.

The male roller 13 is a hollow drum and houses a plurality of blademembers 19 disposed parallel to the axis of the male roller and whichare operatively associated with an indexing mechanism incorporatedwithin and at one end of the roller 13 and to be described later. Themale roller 13 is provided over its surface with a plurality ofspaced-apart slots 20, which are arranged directly above respectiveblade members 19 housed within the roller 13. Each blade member 19 ismounted for reciprocal motion relative to the surface of the male roller13 between a first position wherein the blade member projects above thesurface of the roller through a respective slot 20 and a second positionwherein the blade member is retracted below the surface of the maleroller.

In operation the indexing mechanism, which is adjustable as will bedescribed hereafter, is set so that in the vicinity of the female rollerpreselected blade members 19 are pushed outward of the roller 13,against the force of a biasing means tending to keep them retracted, toproject through a respective slot 20 to perforate film 21 passingbetween the male roller 13 and the female roller 14, those blade members19 not selected by the indexing means remaining retracted. It will benoted that in this embodiment the surface of the female roller 14 is soformed to give a continuous series of circular recesses 22. Theserecesses 22 are complementary to and, in use, receive the perforatingblade heads 23 of the blade members 19. Each preselected blade member 19produces a line of individual perforations 21a transverse the film 21 asshown in FIG. 6. The above mentioned blade member indexing mechanismcomprises a chain and pulley system operatively associated with a seriesof actuating plungers 53 connected to respective blade members 19 byrespective linkages to be described later with reference to FIG. 7. Thechain and pulley system consists of a chain 25, an idler pulley 26 andan adjustable pulley 27 mounted on a slide block 28 which is itselfmounted on the support frame 10. The chain 25 carries a number ofspaced-apart studs 29. In use the chain 25 and its studs 29 are chosento suit the desired perforating operation, i.e. to provide the desireddistance between any two lines of perforations 21a to be applied acrossthe sheet of film 21, by choosing the positions of the studs 29 on thechain such that on rotation of the male roller 13 the studs are broughtin turn opposite respective ones of the actuating plungers 53 of thepreselected blade members only. The required positioning of the studs 29can be achieved either by having a number of chains 25 available withdifferent arrangements of studs 29 for different perforationrequirements, and placing the appropriate chain on the machine whenrequired, or by providing that the studs 29 can be repositioned on thechain as desired. In either case, the indexing mechanism is adjustableto provide for different perforation requirements.

After being brought opposite the selected actuating plungers 53, furtherrotation of the male roller 13 causes the studs 29 to engage therespective plungers 53 which, as will be described with reference toFIG. 7, are caused to project axially out of the roller 13 upon rotationtowards the female roller 14. The engagement of the studs 29 with theselected plungers 53 arrests this axial outward movement of the selectedplungers with the result that through the linkages coupling the plungers53 with their associated blade members 19 the latter are caused toproject from their slots 20 for entering the recesses 22 in the femaleroller to perforate the film. Upon rotation of the blade members 19 awayfrom the female roller 14 after perforation, the plungers 53 withdrawinto the roller 13 and disengage the studs 29, and the preselected blademembers 19 are retracted into their slots 20.

The portion of the indexing mechanism housed within the hollow drum 13comprises a plurality of blade extension and retraction linkages eachcoupling a different plunger 53 to a respective blade member 19--one ofthe linkages being illustrated in FIG. 7. The indexing mechanism furthercomprises a fixed horizontal shaft 51 secured to the support frame 10and protruding into the roller 13 wherein it carries a swash plate 52which does not rotate with the roller 13. Within the roller 13, andadapted to rotate with it, each linkage comprises two plungers 54 and 55linked together and to the actuating plunger 53 by a lever 56. Attachedto the plunger 55 is a rod 57 upon which is mounted a collar 58 whichbears against an angular lever 59. The lever 59 pivots on a disc 60(common to all the linkages) and in turn bears on a nylon bearing plate61 on the blade 19. The indexing mechanism further comprises arespective torsion spring 62 for each blade member 19 tending to biasthe blade member into its retracted position. FIG. 7 shows the relativepositions of the various components of the linkage when the blade member19 is at its furthest point from the female roller 14, and it will beseen that at this point the blade member 19 is held in its retractedposition by the spring 62.

In operation, rotation of the blade member 19 from the furthest pointshown in FIG. 7 towards the female roller 14 causes the plunger 54,which is coupled to the fixed swash plate 52, to perform a rightwardstroke reaching its furthest rightward position when it is closest tothe female roller. Thereafter, the plunger 54 returns to the left to theposition shown in FIG. 7 as the blade member 19 is rotated away from thefemale roller 14 once again.

Assuming that there is no obstruction in the way of actuating plunger53, the latter will, as a result of the coupling lever 56, also stroketo the right during rotation towards the female roller 14 and return tothe left on receding therefrom, since plunger 55 will be held stationaryrelative to the drum by the bias of the spring 62. Thus in this case theblade member 19 will remain retracted during its approach and recessionfrom the female roller and will not take part in the perforatingoperation.

On the other hand, when a chain stud 29 is positioned opposite theplunger 53, the stud 29 will at some point in the rotation towards thefemale roller engage the plunger 53 and arrest the rightward movementthereof. Now, upon further rotation towards the female roller, theplunger 55 will be caused to stroke to the right by the lever 56 insteadof the obstructed plunger 53, thereby overcoming the bias of spring 62and causing the blade member 19 to project from the roller 13. Afterpassing the female roller 14, the plunger 55 will return to the leftallowing the blade member 19 to be retracted by the spring 62, andeventually the plunger 53 will disengage the stud 29.

Thus, by suitably choosing the number and positioning of the studs 29 onthe chain 25 one can select at will those blade members 19 which are topartake in the perforating operation and those which are not.

It will be readily understood that the machine allows for a widevariation in the length of film between imparted transverse lines ofperforations. The indexing mechanism may be adjusted to give the desiredlength of film by choosing the blade members 19 which will react to theengagement of the actuating 53 plungers to project through the slots.The slots may be positioned around the roller surface typically 1 inchapart. Accordingly on a 24 inch circumference roller, sheets of film mayhave applied thereto lines of perforations any distance apart from 1 to24 inches in 1 -inch units.

In practice with high density polyethylene film, good quality perforatedfilm with lines of perforation spaced apart at 10 inch intervals hasbeen produced at a through-put rate of 1200 ft. of film per minutethrough the machine.

While the present invention has been described with particular referenceto the production of perforated sheets of high density polyethylenefilm, it is to be understood that the machine of the present inventionalso has application in applying spaced apart lines of perforation toother film material or like sheet material.

I claim:
 1. A machine for perforating high density polyethylene filmmaterial or the like, comprising a feed roller for supplying filmmaterial to be perforated from a roll thereof, cooperating male andfemale rollers between which film material from the feed roller passesfor perforation, and a take up means for receiving the perforated filmmaterial, the male roller carrying for rotation therewith a plurality ofcircumferentially spaced blade members, means for mounting each bladefor reciprocal motion relative to the surface of the male roller betweena first position wherein the blade member projects from the surface ofthe male roller and a second position wherein the blade member isretracted into the male roller, means for biasing each blade member intoone of its first and second positions, an independently operableactuating member linked respectively to each blade member for forcingthe associated blade member into the other of its first and secondpositions in opposition to the biasing means, an indexing mechanismincluding a plurality of selectively located actuating means mounted formovement in coordination with the rotation of the male roller andarranged to cooperate with the actuating members of the blade members insuch manner that upon rotation of the male roller the actuating meansare brought successively into engagement with selected actuating memberswhereby the associated blade members are successively forced into theirother positions, means for causing the actuating means to remain inengagement with the actuating members during a partial rotation of themale roller and for thereafter being successively disengaged from theactuating members to allow the biasing means to return the blade membersto their one positions, the angular distance over which the actuatingmeans remain in engagement with the selected actuating members beingchosen such that, in the vicinity of the female roller, the blademembers linked with the selected actuating members are in theirprojecting position for perforation of film material passing between themale and female rollers and the blade members linked to the non-selectedactuating members are in their retracted position, recesses within thefemale roller which are entered by the selected blade members duringperforation of the film, and means for adjusting the indexing meanswhereby the spacing and number of actuating means may be changed to varythe selection of blade members.
 2. A machine as claimed in claim 1,wherein a common swash plate and linkage means couples each actuatingmember to its associated blade member, said linkage means beingoperatively positioned relative to said common swash plate such that aseach blade member is rotated towards the female roller the biasing meanscauses the associated actuating member to move relative to the maleroller, and wherein the actuating means moves in coordination with themale roller to engage and arrest the movement of the selected actuatingmembers whereby the associated blade members are forced into their otherposition against the biasing means.
 3. A machine as claimed in claim 2,wherein the biasing means biases each blade member into its retractedposition, and the actuating means moves in coordination with the maleroller to engage the actuating members of the preselected blade memberswhereby the latter are forced to project from the surface of the maleroller.
 4. A machine as claimed in claim 3, wherein the actuating meansmoving in coordination with the male roller comprises a plurality ofstuds secured at selected locations on an endless chain or belt.
 5. Amachine as claimed in claim 1, wherein the blade members are disposedparallel to the axis of the male roller and each comprises a pluralityof blade heads for producing a line of individual perforationstransverse the film material.